Redistribución de tensiones en secciones transversales ejecutadas por fases sucesivas

Stress redistribution in evolutive cross-sections

In this paper a well-known method of caltulating the self-stress state appearing in a section following Navier's Law is presented. The cross-section may be formed by concrete of different ages, prestressed and non-prestressed reinforcement and even by a section of steel. General formulae are deduced from equilibruim and compatibility requirementes at each layer's interface. For the analysis of the time-dependent changes, the consideration of a particular creep function is needed. Thus, simplified CEB-1990 Product Model is compared to the CEB-1970 one; and a particular case of cross-section fabricated in two parts within a time-interval of 100 days is studied. The use of simplified formulae and a single step of time, seems to be a quite good accurate approach as compared to the namely exact step-by-step calculation approach.